Buggy code:
public class LatexFilter extends BackendFilter { public LatexFilter ( Context context ) { } public LatexFilter ( Context context , String indent ) { } protected String endl = System . getProperty ( "line.separator" ) ; private StringBuilder preamble = new StringBuilder ( ) ; private boolean firstProduction = false ; private boolean terminalBefore = false ; private Map < String , String > colors = new HashMap < String , String > ( ) ; private LatexPatternsVisitor patternsVisitor = new LatexPatternsVisitor ( context ) ; private boolean firstAttribute ; private boolean hasTitle = false ; private String indent = "" ; public LinkedList < Boolean > getWantParens ( ) { } private LinkedList < Boolean > wantParens = new LinkedList < Boolean > ( ) ; public void setResult ( StringBuilder result ) { } public StringBuilder getPreamble ( ) { } private void increaseIndent ( ) { } private void decreaseIndent ( ) { } private void newLine ( ) { } private boolean isOnNewLine ( ) { } private void decreaseIndentAndNewLineIfNeeded ( ) { } @ Override public Void visit ( Definition def , Void _void ) { } @ Override public Void visit ( PriorityExtended node , Void _void ) { } @ Override public Void visit ( PriorityExtendedAssoc node , Void _void ) { } @ Override public Void visit ( Module mod , Void _void ) { } @ Override public Void visit ( Syntax syn , Void _void ) { } @ Override public Void visit ( NonTerminal sort , Void _void ) { } @ Override public Void visit ( Production p , Void _void ) { } @ Override public Void visit ( Terminal pi , Void _void ) { } @ Override public Void visit ( UserList ul , Void _void ) { } @ Override public Void visit ( Lexical t , Void _void ) { } @ Override public Void visit ( Configuration conf , Void _void ) { } @ Override public Void visit ( Cell c , Void _void ) { } public Void visit ( Collection col , Void _void ) { } private boolean containsBR ( Collection col ) { } private void printList ( List < Term > contents , String str , boolean addNewLine ) { } public Void visit ( TermComment tc , Void _void ) { } @ Override public Void visit ( Variable var , Void _void ) { } private String makeIndices ( String str ) { } private String makeGreek ( String name ) { } @ Override public Void visit ( ListTerminator e , Void _void ) { } private void printEmpty ( String sort ) { } @ Override public Void visit ( Rule rule , Void _void ) { } @ Override public Void visit ( org . kframework . kil . Context cxt , Void _void ) { } @ Override public Void visit ( Hole hole , Void _void ) { } @ Override public Void visit ( Rewrite rew , Void _void ) { } @ Override public Void visit ( Bracket trm , Void _void ) { } @ Override public Void visit ( TermCons trm , Void _void ) { } @ Override public Void visit ( KLabelConstant c , Void _void ) { } @ Override public Void visit ( Token t , Void _void ) { } @ Override public Void visit ( KSequence k , Void _void ) { } @ Override public Void visit ( KApp app , Void _void ) { } @ Override public Void visit ( KList list , Void _void ) { } @ Override public Void visit ( LiterateDefinitionComment comment , Void _void ) { } @ Override public Void visit ( LiterateModuleComment comment , Void _void ) { } @ Override public Void visit ( Attribute entry , Void _void ) { if ( context . isParsingTag ( entry . getKey ( ) ) ) return null ; if ( entry . getKey ( ) . equals ( Attribute . keyOf ( "latex" ) ) ) return null ; if ( entry . getKey ( ) . equals ( Attribute . keyOf ( "html" ) ) ) return null ; if ( firstAttribute ) { firstAttribute = false ; } else { result . append ( ",<seq2seq4repair_space>" ) ; } result . append ( ( ( "\\kattribute{" + ( StringUtil . latexify ( entry . getKey ( ) . toString ( ) ) ) ) + "}" ) ) ; <START_BUG> String value = entry . toString ( ) ; <END_BUG> if ( ! ( value . isEmpty ( ) ) ) { result . append ( ( ( "(" + ( StringUtil . latexify ( value ) ) ) + ")" ) ) ; } return null ; } @ Override public Void visit ( Attributes attributes , Void _void ) { } }

Fix:
String value = entry . getValue ( ) . toString ( ) ;